Another BBC television show in book form. Another example of good illustration and stylish writing. Yet it doesn't quite satisfy. Perhaps the theme--grand schemes of dreamers/optimists--begins to pall after a while. Or sound too Boy Scout-escapist in the light of daily reality. We have heard about Gerard O'Neill and his human colonies in space. We have listened to the architects with their bubble cities or megastructures. New to us were Theodore Taylor's Santa Claus machines which would mine space, separate out elements by mass spectrography, and manufacture with them what you will. . . and the Bernal sphere around the sun which predates O'Neill's colonies. Then there are the machines which can take you out to the asteroids or the ones powered by fusion of nuclear pellets which can fire you starwards. Back on earth there are the dreams of soilless agriculture, fish farming, solar energy converters. Mind you, we are not against dreams--especially dreams that money can buy and which could be tried locally to relieve problems on earth. But many of the schemes are pricey, or else are predicated on fanciful notions of how human beings behave. To the book's credit, some of these issues are aired, as well as the close relationship between any venture in space and its military potential. Even the possibility of sub-speciation is considered. The molecular biologist Sol Spiegelman is quoted as facetiously suggesting that DNA created man to exploit all possible niches for replication--with just enough pressure on earth to make him itch to explore space. We agree that the itch is there. And that it can be noble. It just shouldn't blind us to getting on with the mundane jobs that should be done in this world.